Pulp composition and paper



Patented Nov. 10, 1942 2,301,452 PULR COMPOSITION AND PAPER.

Joseph E. Plumstead, Wilmington, DeL, assignor, by mesne assignments, to West Virginia Pulp & Paper Company, New York, N. Y., a corporation of Delaware No Drawing. Original application September 4,

1931, Serial No. 561,241. Divided and this application June 29, 1940, Serial No. 343,095

9 Claims.

This invention relates to an improved pulp composition and to paper formed therefrom. The present application is a division of my copending application Ser. No. 561,241 filed September 4, 1931, now Patent No. 2,235,531 granted March 18, 1941. In said parent case there are disclosed and claimed methods of producing certain pigment or filler materials.

The invention embraced by the present application relates to a pulp mixture containing mechanical'or ground wood pulp and a substance which serves both as a filler and as an age deterrent.

Paper containing any substantial amount of mechanical or ground wood pulp has, been found ordinarily to deteriorate rapidly with age. However, certain substances such as sulfites of alkaline earth metals, and particularly calcium sulfite, have been found to have an age deterrent vent the yellowing, due to age and exposure to air and sunlight, of paper containing it. Thus, when added as a filler to paper formed from or containing mechanical wood pulp, it not only enhances the original whiteness of the paper but it tends to preserve such'whiteness.

.Other features and advantages of the invention will appear from the detailed description of the same which will now be given.

For a full description of various methods and forms of apparatus by which age deterrent fillers of the types contemplated by the present invenpulp having calcium sulfite as an age deterrent filler distributed therethrough'.

3'. As an article of manufacture a sheet of paper formed at least in part of mechanical wood pulp and containing at least one sulfite of the group consisting of calcium sulfite and magnesium sulfite as-an age deterrent filler.

4, A composition comprising mechanical wood pulp having at least one sulfite of the group consisting'of calcium sulfite and magnesium sulfite as an age deterrent filler distributed theretion may be produced, reference may be had to said parent Patent No. 2,235,531. These fillers are particularly valuable for paper made from mechanical or ground wood pulp. The reducing action of the calcium sulfite, for example, to- I or an equivalent substance is intended, and that the claims are not to be restricted to calcium. In the use of the improved pigment or flller in the production of paper. it may be added to the tion of paper therefrom a finelydivided filler including calcium sulfite as an age deterrent.

8. A method of deterring the aging of paper containing mechanical wood pulp which comprises intermixing with the pulp prior to formation of paper therefroma a finely divided filler including at least one sulfite of the group consisting of calcium sulfite and magnesium sulfite as an age deterrent.

9. A method of deterring the aging of paper containing mechanical wood pulp which comprises introducing between the fibers thereof a finely divided filler including at least one sulfite of the group consisting of calcium sulfite and magnesium sulfite as an age deterrent.

JOSEPH E. PLUMSTE'AD. 

